An evaluation of processor co-allocation for different system configurations and job structures

In systems consisting of multiple clusters of processors such as our Distributed ASCI Supercomputer (DAS), jobs may request co-allocation, i.e., the simultaneous allocation of processors in different clusters. We simulate such systems ignoring communication among the tasks of jobs, and determine the response times for different types and sizes of job requests, and for different numbers and sizes of clusters. In many cases we also compute or approximate the maximum utilization. We find that the numbers and sizes of the clusters and of the job components have a strong impact on performance, and that in many cases co-allocation is a viable choice.